. >> authorities in vallejo are getting help from the fbi and the atf to investigate that fire at the private law office of the vallejo mayor. they have called the fire an act of terrorism because davis is a high profile figure. the fire broke out around 1:30 yesterday morning. the office suffered significant damage and many of his client records were destroyed. >> happening now the 30th yearly oracle open world user conference getting started. 50,000 people are registered to attend. the areaa hound howard street is expected to be blocked and driver also likely experience delays. ceo larry ellison is scheduled to give the key note address this evening. it's expected to be a economic shot in the arm for city hotels, restaurants, cabs and retailers. >> really huge impact to the city. i think it brings a lot of revenue and we are lucky to have it. >> reporter: they are also expected to announce a mapping deal with nokia. open world runs through october 4th. > a air quality is forecast to be unhealthy for a third day in a row in the bay area leading officials to declare at spare the area